Fix single library test.

pkg/docgen/lib/docgen.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// **docgen** is a tool for creating machine readable representations of Dart
 /// code metadata, including: classes, members, comments and annotations.
 ///
 /// docgen is run on a `.dart` file or a directory containing `.dart` files.
 ///
 ///      $ dart docgen.dart [OPTIONS] [FILE/DIR]
@@ skipping 141 matching lines @@
   if (library != null) {
     library.packageName = packageName;
     // If we are the main library in a package, associate the package readme
     // with us.
     // TODO(alanknight): We can't really rely on all packages having a library
     // that matches the package name. Need a better way to store this.
     if (library.packageName == library.name) {
       library.packageIntro = _packageIntro(rootdir);
     }
   }
-  return packageName + '/';
+  return packageName;
 }
 
 String _packageIntro(packageDir) {
   var dir = new Directory(packageDir);
   var files = dir.listSync();
   var readmes = files.where((FileSystemEntity each) => (each is File &&
       each.path.substring(packageDir.length + 1, each.path.length)
           .startsWith('README'))).toList();
   if (readmes.isEmpty) return '';
   // If there are multiples, pick the shortest name.
@@ skipping 366 matching lines @@
 String _htmlMdn(String content, String url) {
   return '<div class="mdn">' + content.trim() + '<p class="mdn-note">'
       '<a href="' + url.trim() + '">from Mdn</a></p></div>';
 }
 
 /// Look for the specified name starting with the current member, and
 /// progressively working outward to the current library scope.
 String findElementInScope(String name, LibraryMirror currentLibrary,
     ClassMirror currentClass, MemberMirror currentMember) {
   var packagePrefix = _findPackage(currentLibrary);
+  if (packagePrefix != '') packagePrefix += '/';
 
   determineLookupFunc(name) => name.contains('.') ?
       dart2js_util.lookupQualifiedInScope :
       (mirror, name) => mirror.lookupInScope(name);
   var lookupFunc = determineLookupFunc(name);
 
   var memberScope = currentMember == null ?
       null : lookupFunc(currentMember, name);
   if (memberScope != null) return packagePrefix + docName(memberScope);
 
@@ skipping 833 matching lines @@
 /// Remove statics from the map of inherited items before adding them.
 Map _filterStatics(Map items) {
   var result = {};
   items.forEach((name, item) {
     if (!item.isStatic) {
       result[name] = item;
     }
   });
   return result;
 }